A small group of Bahraini women, carrying national flags and a banner supporting political prisoners, march quickly between police patrols, on the lookout for violators of a protest ban, in Manama, Bahrain, Friday, May 1, 2015. The government denied permission for Labor Day protests, so protesters in several opposition areas went out in small groups for quick marches between police patrols. The banner reads: “Revolution of Chains, in solidarity with Jaw central prison inmates”. (Photo by Hasan Jamali/AP Photo)

A small group of Bahraini men, carrying national flags and signs, march quickly between police patrols, on the lookout for violators of a protest ban, in Manama, Bahrain, Friday, May 1, 2015. (Photo by Hasan Jamali/AP Photo)

Bricklayers shout labor day slogans as they take part in a May Day march, in La Paz, Bolivia, Friday, May 1, 2015. Left-wing groups, governments and trade unions were staging rallies around the world Friday to mark International Workers Day, also known as May Day. (Photo by Juan Karita/AP Photo)

Demonstrators shout slogans as they take part in a May Day march, in La Paz, Bolivia, Friday, May 1, 2015. (Photo by Juan Karita/AP Photo)

A member of the Mapuche ethnic group from Chile participates in a rally commemorating International Workers' Day in La Paz May 1, 2015. International Workers' Day, also known as Labour Day or May Day, commemorates the struggle of workers in industrialised countries in the 19th century for better working conditions. (Photo by David Mercado/Reuters)

Bolivian children participate in a rally commemorating International Workers' Day in La Paz May 1, 2015. (Photo by David Mercado/Reuters)

Bolivian children participate in a rally commemorating International Workers' Day in La Paz May 1, 2015. Bolivian children are allowed to work from the age of 10, according to a law enacted in July 2014, according to local media. International Workers' Day, also known as Labour Day or May Day, commemorates the struggle of workers in industrialised countries in the 19th century for better working conditions. (Photo by David Mercado/Reuters)

Demonstrators shout anti-government slogans as they take part in a May Day march, in La Paz, Bolivia, Friday, May 1, 2015. (Photo by Juan Karita/AP Photo)

A woman walks in front of a banner with a message that reads in Spanish; “Long live political independence and unions”, in a May Day march, in La Paz, Bolivia, Friday, May 1, 2015. (Photo by Juan Karita/AP Photo)

A protester wearing a toy British police helmet and an Anonymous mask takes a picture during a rally at the end of a May Day demonstration march in Trafalgar Square in London, Friday, May 1, 2015. Tens of thousands of workers marked May Day in European cities with a mix of anger and gloom over austerity measures imposed by leaders trying to contain the eurozone's intractable debt crisis. (Photo by Matt Dunham/AP Photo)

A silver street performer dressed as Colombian singer Carlos Vives sings during a May Day march in Bogota, Colombia, Friday, May 1, 2015. Left-wing groups, governments and trade unions were staging rallies around the world Friday to mark International Workers Day also known as May Day. (Photo by Fernando Vergara/AP Photo)

A man walks past smoke left by tear gas during clashes against police on Labor Day in Bogota, Colombia May 1, 2015. (Photo by Jose Miguel Gomez/Reuters)

A man shouts slogans during protests for Labor Day in Bogota, Colombia May 1, 2015. (Photo by Jose Miguel Gomez/Reuters)

A demonstrator throws a stone during clashes against police on Labor Day in Bogota, Colombia May 1, 2015. (Photo by Jose Miguel Gomez/Reuters)

A demonstrator throws a stone during clashes against police on Labor Day in Bogota, Colombia May 1, 2015. (Photo by Jose Miguel Gomez/Reuters)

A man shouts slogans during protests for Labor Day in Bogota, Colombia May 1, 2015. International Workers' Day, also known as Labour Day or May Day, commemorates the struggle of workers in industrialised countries in the 19th century for better working conditions. (Photo by Jose Miguel Gomez/Reuters)

A demonstrator walks in front riot policemen during protests for Labor Day in Bogota, Colombia May 1, 2015. (Photo by Jose Miguel Gomez/Reuters)

A demonstrator shouts slogans during protests for Labor Day in Bogota, Colombia May 1, 2015. (Photo by Jose Miguel Gomez/Reuters)

A demonstrator shouts slogans during protests for Labor Day in Bogota, Colombia May 1, 2015. (Photo by Jose Miguel Gomez/Reuters)

A man dressed in military regalia shouts slogans against the government of Colombia's President Juan Manuel Santos during a May Day march in Bogota, Colombia, Friday, May 1, 2015. (Photo by Fernando Vergara/AP Photo)

Cuban army cadets react to the photographer as they march in Revolution Square marking May Day, in Havana, Cuba, Friday, May 1, 2015. (Photo by Ramon Espinosa/AP Photo)

Cubans march in the rain on Revolution Square marking May Day, in Havana, Cuba, Friday, May 1, 2015. (Photo by Ramon Espinosa/AP Photo)

Cuban Army soldiers hold a giant Cuban flag as they march in Revolution Square marking May Day, in Havana, Cuba, Friday, May 1, 2015. (Photo by Ramon Espinosa/AP Photo)

A woman dressed in a skirt with a picture of the revolutionary hero Ernesto “Che” Guevara marches during a May Day parade in Havana May 1, 2015. International Workers' Day, also known as Labour Day or May Day, commemorates the struggle of workers in industrialised countries in the 19th century for better working conditions. (Photo by Enrique De La Osa/Reuters)

A child takes part in a May Day parade in Havana May 1, 2015. (Photo by Enrique De La Osa/Reuters)

A Cuban Navy soldier carries a child on his shoulders as they march in Revolution Square marking May Day, in Havana, Cuba, Friday, May 1, 2015. Thousands of people converged on the plaza for the traditional march, led this year by President Raul Castro and Venezuelan President Nicolas Maduro. (Photo by Ramon Espinosa/AP Photo)

Cubans take part in a May Day parade in Havana May 1, 2015. (Photo by Enrique De La Osa/Reuters)

A woman holds up a handwritten sign against the U.S embargo during a march in Revolution Square marking May Day, in Havana, Cuba, Friday, May 1, 2015. (Photo by Ramon Espinosa/AP Photo)

Venezuela's President Nicolas Maduro, left, and Cuba' President Raul Castro acknowledge marchers as they parade past marking May Day in Revolution Square, in Havana, Cuba, Friday, May 1, 2015. (Photo by Ramon Espinosa/AP Photo)

Cubans hold a a banner with an image of the late Venezuelan President Hugo Chavez and Cuban leader Fidel Castro, as they march in Revolution Square marking May Day, in Havana, Cuba, Friday, May 1, 2015. (Photo by Ramon Espinosa/AP Photo)

Cubans march under the rain for May Day at Revolution square in Havana, Cuba, Friday May 1, 2015. (Photo by Ramon Espinosa/AP Photo)

A man holds a Cuban flag after a May Day parade in Havana May 1, 2015. (Photo by Reuters/Stringer)

Women wearing metallic flyaway eye masks and their country's national flag, take part in the May Day parade, in a show of support for Ecuador's President Rafael Correa, in Quito, Ecuador, Friday, May 1, 2015. (Photo by Dolores Ochoa/AP Photo)

Marchers shout anti-government slogans as they dance with a Chinese dragon representing Ecuador's President Rafael Correa for his many collaborations with the Chinese government, during a march called by labor unions to mark May Day, in Quito, Ecuador, Friday, May 1, 2015. Rallies were staged around the world Friday to mark International Workers Day, also known as May Day. (Photo by Dolores Ochoa/AP Photo)

Women march hand in hand as they take part in the May Day parade, in Quito, Ecuador, Friday, May 1, 2015. Left-wing groups, governments and trade unions were staging rallies around the world Friday to mark International Workers Day, also known as May Day. (AP Photo/Dolores Ochoa)

Ecuadorean supporters of President Rafael Correa march to commemorate International Workers' Day, on the streets of Quito May 1, 2015. (Photo by Guillermo Granja/Reuters)

A parade float that represents the lack of freedom by encaging a rat and a clown, surrounded by images of Ecuador's President Rafael Correa and the community leaders who support him, arrives at the San Francisco Plaza at the end of an anti-government march, marking May Day, in Quito, Ecuador, Friday, May 1, 2015. (Photo by Dolores Ochoa/AP Photo)

Workers march holding umbrellas marked with palm prints, symbolizing clean hands, free of corruption, during a May Day parade in a show of support for Ecuador's President Rafael Correa, in Quito, Ecuador, Friday, May 1, 2015. (Photo by Dolores Ochoa/AP Photo)

Ecuador's President Rafael Correa, third from the right, marches in the May Day parade in Quito, Ecuador, Friday, May 1, 2015. (Photo by Dolores Ochoa/AP Photo)

Confetti litters the parade route as workers take part in the May Day parade in Quito, Ecuador, Friday, May 1, 2015. (Photo by Dolores Ochoa/AP Photo)

People walk during a May Day march through Berlin's Kreuzberg district, Germany, May 1, 2015. (Photo by Hannibal Hanschke/Reuters)

Masked protestors walk during a May Day march through Berlin's Kreuzberg district, Germany, May 1, 2015. The text over the red star reads “We are everywhere”. (Photo by Hannibal Hanschke/Reuters)

Protesters clash with police during a May Day march in Hamburg, Germany, May 1, 2015. (Photo by Hannibal Hanschke/Reuters)

Masked protestors walk during a May Day march through Berlin's Kreuzberg district, Germany, May 1, 2015. (Photo by Hannibal Hanschke/Reuters)

Police detain a demonstrator during clashes at a May Day march in Hamburg, Germany, May 1, 2015. (Photo by Fabian Bimmer/Reuters)

Police arrest two demonstrators during clashes at a May Day march in Hamburg, Germany, May 1, 2015. (Photo by Fabian Bimmer/Reuters)

Protesters sit on a street in front of water cannons during clashes with Police forces at a May Day march in Hamburg, Germany, May 1, 2015. (Photo by Fabian Bimmer/Reuters)

Masked protestors are seen in front of a banner, which reads “Class against Class” during a May Day march in Hamburg, Germany, May 1, 2015. (Photo by Fabian Bimmer/Reuters)

In this May 1, 2015 photo riot police officers walk pass flares during a May Day demonstration in Hamburg, Germany. (Photo by Markus Scholz/AP Photo/DPA)

Protesters from the Communist-affiliated trade union PAME hold red flags during a May Day rally in front of the parliament building in Athens May 1, 2015. (Photo by Alkis Konstantinidis/Reuters)

A man wearing a carnation at his lapel reads a newspaper during a May Day rally in front of the parliament building in Athens May 1, 2015. (Photo by Alkis Konstantinidis/Reuters)

Protesters from the Communist-affiliated trade union PAME hold red flags during a May Day rally in Athens May 1, 2015. The words on the vest read: “Construction workers syndicate”. (Photo by Alkis Konstantinidis/Reuters)

A member of a brass band plays an instrument during a rally to mark May Day in Gauhati, India, Friday, May 1, 2015. May 1 is celebrated as the International Labor Day or May Day across the world. (Photo by Anupam Nath/AP Photo)

People hold placards during a May Day rally in Jakarta, Indonesia, May 1, 2015. Thousands of workers urged the government to raise minimum wages and improve working condition, according to local media. (Photo by Reuters/Beawiharta)

Thousands of Indonesian workers march during a May Day rally in Jakarta, May 1, 2015. (Photo by Reuters/Beawiharta)

Policemen stand guard in front of the Presidential palace as workers hold a protest during a May Day rally in Jakarta, Indonesia, May 1, 2015. (Photo by Reuters/Beawiharta)

People carry a national flag as they march during a May Day rally in Jakarta, Indonesia, May 1, 2015. (Photo by Reuters/Beawiharta)

People gather in mass Friday prayer during a May Day rally in Jakarta, Indonesia, May 1, 2015. (Photo by Reuters/Beawiharta)

People carry a national flag as they march during a May Day rally in Jakarta, Indonesia, May 1, 2015. (Photo by Reuters/Beawiharta)

A demonstrator wears a mask of Indonesia President Joko Widodo during a May Day rally in Jakarta, Indonesia, May 1, 2015. (Photo by Reuters/Beawiharta)

Policemen stand guard as workers hold a May Day rally at a business district in Jakarta, Indonesia, May 1, 2015. (Photo by Reuters/Beawiharta)

Supporters of the Iraqi Communist Party take part in a May Day celebration in Baghdad, Iraq, Friday, May 1, 2015. May 1 is celebrated as the International Labor Day or May Day across the world. (Photo by Hadi Mizban/AP Photo)

A supporter of the Iraqi Communist Party takes part in a May Day celebration in Baghdad, Iraq, Friday, May 1, 2015. (Photo by Hadi Mizban/AP Photo)

Supporters of the Iraqi Communist Party take part in a May Day celebration in Baghdad, Iraq, Friday, May 1, 2015. (Photo by Hadi Mizban/AP Photo)

Protesters run during a march for Labor Day in Mexico City May 1, 2015. (Photo by Edgard Garrido/Reuters)

Demonstrators take part during a march for Labour Day in Mexico City May 1, 2015. (Photo by Edgard Garrido/Reuters)

An indigenous woman and her daughter look at a march for Labor Day in Mexico City May 1, 2015. (Photo by Edgard Garrido/Reuters)

Protesters hold a flag during a march for Labor Day in Mexico City May 1, 2015. (Photo by Edgard Garrido/Reuters)

A woman holds a Mexico flag as a man takes a selfie picture during a march for Labor Day in Mexico City May 1, 2015. (Photo by Edgard Garrido/Reuters)

Police officers on motorcycles watch over a march for Labor Day in Mexico City May 1, 2015. (Photo by Edgard Garrido/Reuters)

Protesters wearing Guy Fawkes masks take part in a march for Labor Day in Mexico City May 1, 2015. (Photo by Edgard Garrido/Reuters)

Protesters run during a march for Labor Day in Mexico City May 1, 2015. (Photo by Edgard Garrido/Reuters)

Protesters spray-paint slogans on the wall of a bank during a march for Labour Day in Chilpancingo, Mexico May 1, 2015. (Photo by Daniel Becerril/Reuters)

A protester holds up a machete during a march for Labour Day in Chilpancingo, Mexico May 1, 2015. (Photo by Daniel Becerril/Reuters)

Masked protesters take part in a march for Labour Day in Chilpancingo, Mexico May 1, 2015. (Photo by Daniel Becerril/Reuters)

A protester spray-paints slogans on the wall of a HSBC bank branch during a march for Labour Day in Chilpancingo, Mexico May 1, 2015. The slogan the man is currently spray-painting reads, “Without solution, there will be no election”. (Photo by Daniel Becerril/Reuters)

People throw smoke grenades during the annual Labour Day protest in front of Presidential Office in Taipei, Taiwan, May 1, 2015. Thousands of people marched to demand higher wages and labour rights, according to local media. The head banner reads, “shorten working hours; no overfatigue”. (Photo by Patrick Lin/Reuters)

Workers burned an effigy of Philippine President Benigno Aquino during a May Day protest outside the presidential palace in Manila May 1, 2015. (Photo by Romeo Ranoco/Reuters)

People march during a rally to celebrate International Workers' Day in Asuncion May 1, 2015. The posters read: “Present Humanities” (L), “Education is not a privilege but a right” (R) and “Education without barriers” (C). (Photo by Jorge Adorno/Reuters)

Workers march during the May Day celebration in San Salvador May 1, 2015. (Photo by Jose Cabezas/Reuters)

A man holds a banner with an image depicting Brazil's President Dilma Rousseff during a rally to commemorate International Workers' Day, in Sao Paulo May 1, 2015. (Photo by Nacho Doce/Reuters)

A demonstrator sports a tattoo showing the symbol of the Italian Communist party during a protest against the Expo 2015 fair in Milan, Italy, Friday, May 1, 2015. (Photo by Luca Bruno/AP Photo)

A man entertains with a traditional musical instrument during a Labour Day rally in Lagos on May 1, 2015. Tens of thousands of people across the globe were hitting the streets on May 1 for mass rallies marking International Labour Day. (Photo by Pius Utomi Ekpei/AFP Photo)

A Pakistani woman shouts slogans at a rally to observe the Labor Day in Peshawar, Pakistan, Friday, May 1, 2015. Pakistan observed International Labor Day with other nations worldwide. (Photo by Mohammad Sajjad/AP Photo)

Portuguese Maria da Luz, 88, wearing a red carnation on her coat, shouts slogans during a march marking the international May Day, in Lisbon, Friday, May 1, 2015. A red carnation is the symbol of the revolution that restored the democracy in Portugal in 1974. (Photo by Francisco Seco/AP Photo)

People shout slogans during a march marking the international May Day, in Lisbon, Friday, May 1, 2015. (Photo by Francisco Seco/AP Photo)

Workers shout slogans against austerity measures during a march by the Portuguese union CGTP in Lisbon May 1, 2015. (Photo by Hugo Correia/Reuters)

Workers shout slogans against austerity measures during a march by the Portuguese union CGTP in Lisbon May 1, 2015. (Photo by Hugo Correia/Reuters)

A woman, wearing a red carnation in her hair, sings a protest song during a march marking the international May Day, in Lisbon, Friday, May 1, 2015. (Photo by Francisco Seco/AP Photo)

People, some holding red carnations, shout slogans during a march marking the international May Day, in Lisbon, Friday, May 1, 2015. (Photo by Francisco Seco/AP Photo)

People, some wearing red carnations in their hair, play music and dance during a march marking the international May Day, in Lisbon, Friday, May 1, 2015. (Photo by Francisco Seco/AP Photo)

A restauramt waiter looks through a window reflecting communist demonstrators during a May Day demonstration in downtown Moscow, Russia, Friday, May 1, 2015. As in Soviet times, tens of thousands of cheerful workers paraded across Red Square despite a chilly rain, but instead of red flags with the Communist hammer and sickle, they waved the blue flags of the dominant Kremlin party and the Russian tricolor. Participants, who came in groups organized by their trade unions, said the May 1 parade was a tradition going back to their childhood. (Photo by Denis Tyrin/AP Photo)

Communists carry a portrait of former Soviet leader Josef Stalin as they march along Kremlin Towers during a May Day demonstration in Moscow, Friday, May 1, 2015. (Photo by Denis Tyrin/AP Photo)

Communists carry a poster depicting U.S. President Barack Obama during a traditional May Day march in St.Petersburg, Russia, Friday, May 1, 2015. (Photo by Dmitry Lovetsky/AP Photo)

People walk with flags at Red Square during a May Day rally in Moscow May 1, 2015. (Photo by Maxim Zmeyev/Reuters)

People walk with flags and banners at Red Square during a May Day rally in Moscow May 1, 2015. The placard reads, “Let's turn Moscow into a comfortable and safe city”. (Photo by Maxim Zmeyev/Reuters)

People walk with flags and banners along a bridge over the Golden Horn bay during a May Day rally in the Russian far-eastern city of Vladivostok May 1, 2015. (Photo by Yuri Maltsev/Reuters)

People walk with flags and artificial flowers at Red Square during a May Day rally in Moscow May 1, 2015. (Photo by Maxim Zmeyev/Reuters)

A man plays a traditional drum during a May Day rally in the Russian far-eastern city of Vladivostok May 1, 2015. (Photo by Yuri Maltsev/Reuters)

Men play accordions during a May Day rally along a bridge over the Golden Horn bay in the Russian far-eastern city of Vladivostok May 1, 2015. (Photo by Yuri Maltsev/Reuters)

Gennady Zyuganov, leader of Russia's Communist party, attends a May Day rally in Moscow May 1, 2015. (Photo by Maxim Shemetov/Reuters)

Supporters of Russia's Communist party carry banners and flags during a May Day rally in Moscow May 1, 2015. (Photo by Maxim Shemetov/Reuters)

Stilt walkers take part in a May Day rally of Russia's Communist party in Moscow May 1, 2015. (Photo by Maxim Shemetov/Reuters)

Supporters of Russia's Communist party sing as they take part in a May Day rally in Moscow May 1, 2015. International Workers' Day, also known as Labour Day or May Day, commemorates the struggle of workers in industrialised countries in the 19th century for better working conditions. (Photo by Maxim Shemetov/Reuters)

A supporter of Russia's Communist party attends a May Day rally in Moscow May 1, 2015. (Photo by Maxim Shemetov/Reuters)

A supporter of Russia's Communist party wears a t-shirt with an image of Soviet state founder Vladimir Lenin during a May Day rally in central Stavropol May 1, 2015. (Photo by Eduard Korniyenko/Reuters)

A supporter of Russia's Communist party holds a flag during a May Day rally in Moscow May 1, 2015. (Photo by Maxim Shemetov/Reuters)

Communists carry a flag depicting Vladimir Lenin, the Soviet Union founder, during a tradition May Day march in St. Petersburg, Russia, Friday, May 1, 2015. (Photo by Dmitry Lovetsky/AP Photo)

Russian Communist party members and supporters move to the center of Moscow during a traditional May Day demonstration, Russia, 01 May 2015. Some 140,000 workers and students attended the parade on the occasion of Labour Day, also known as International Worker's Day or May Day. (Photo by Maxim Shipenkov/EPA)

Communists carry portraits of former Soviet leaders Josef Stalin, left, and Vladimir Lenin as they march along Kremlin Towers during a May Day demonstration in Moscow, Friday, May 1, 2015. (Photo by Denis Tyrin/AP Photo)

Communists carry a poster depicting U.S. President Barack Obama during a traditional May Day march in St.Petersburg, Russia, Friday, May 1, 2015. (Photo by Dmitry Lovetsky/AP Photo)

Communists march with red flags and a banners along Kremlin Towers during May Day demonstration in Moscow, Friday, May 1, 2015. (Photo by Denis Tyrin/AP Photo)

Workers shout slogans as they march on the street during May Day, in Pamplona northern Spain, Friday, May 1, 2015. Tens of thousands of workers marked May Day in European cities with a mix of anger and gloom over austerity measures imposed by leaders trying to contain the eurozone's intractable debt crisis. (Photo by Alvaro Barrientos/AP Photo)

Demonstrators of the General Confederation of Work (CGT) lay down a giant flag during May Day celebrations in Valencia, Spain, May 1, 2015. (Photo by Heino Kalis/Reuters)

Workers and union members hold banners and flags of the General Workers Union (UGT) and Comisiones Obreras (CCOO) during a May Day rally in Malaga, Spain May 1, 2015. The banner reads, “This way we would not get out of the crisis”. (Photo by Jon Nazca/Reuters)

People wave a second Spanish Republic flag (C) and Communist flags during a May Day rally in Malaga, Spain May 1, 2015. (Photo by Jon Nazca/Reuters)

A man holds a Communist flag as he shouts slogans during a May Day rally in Malaga, Spain May 1, 2015. (Photo by Jon Nazca/Reuters)

People carry a second Spanish Republic flag (R) and Communist flags after a May Day rally in Malaga, Spain May 1, 2015. (Photo by Jon Nazca/Reuters)

People carry a Second Spanish Republic flag and Communist flags after a May Day rally in Malaga, Spain May 1, 2015. (Photo by Jon Nazca/Reuters)

Workers and union members of the General Workers Union (UGT) attend a May Day rally in Malaga, Spain, May 1, 2015. (Photo by Jon Nazca/Reuters)

Demonstrators of Spain's leading trade unions CCOO and UGT march during May Day celebrations in Valencia, Spain, May 1, 2015. (Photo by Heino Kalis/Reuters)

Turkish riot police officers hold their positions during clashes with demonstrators in Istanbul, Turkey, Friday, May 1, 2015. Clashes erupted between police and May Day demonstrators in Istanbul on Friday as crowds determined to defy a government ban tried to march to the city's iconic Taksim Square. Security forces pushed back demonstrators with a water cannon and tear gas. (Photo by Emrah Gurel/AP Photo)

A demonstrator throw a firebomb during clashes with Turkish riot police officers in Istanbul, Turkey, Friday, May 1, 2015. The government assigned 30,000 police officers backed by helicopters as workers and demonstrators determined to defy a government ban, tried to march to iconic Taksim Square, where 35 people were killed during May Day celebration in 1977. (Photo by Emrah Gurel/AP Photo)

A boy kicks a ball as policemen block streets to prevent people from gathering for May Day demonstrations near Taksim Square in Istanbul, Turkey, May 1, 2015. Istanbul went into a security lockdown on Friday as thousands of Turkish police manned barricades and closed off streets to traffic to stop May Day rallies at the central Taksim Square, a symbolic point for anti-government protests. (Photo by Umit Bektas/Reuters)

Two vendors watch the street from their shop window as policemen block streets to prevent people from gathering for May Day demonstrations near Taksim Square in Istanbul, Turkey, May 1, 2015. (Photo by Umit Bektas/Reuters)

A demonstrator holds a flag as policemen block streets to prevent people from gathering for May Day demonstrations near Taksim Square in Istanbul, Turkey, May 1, 2015. (Photo by Umit Bektas/Reuters)

Protesters take cover as they clash with police near Taksim Square in Istanbul, Turkey, May 1, 2015. (Photo by Huseyin Aldemir/Reuters)

A protester is detained by policemen during clashes near Taksim Square in Istanbul, Turkey, May 1, 2015. (Photo by Huseyin Aldemir/Reuters)

A protester looks on during clashes with police in Okmeydani neighborhood in Istanbul, Turkey, May 1, 2015. (Photo by Huseyin Aldemir/Reuters)

A protester uses a catapult during clashes with police in Okmeydani neighborhood of Istanbul, Turkey, May 1, 2015. (Photo by Huseyin Aldemir/Reuters)

A protester holds a bottle during clashes with police in Okmeydani neighborhood in Istanbul, Turkey, May 1, 2015. (Photo by Huseyin Aldemir/Reuters)

A protester runs during clashes with police in Okmeydani neighborhood in Istanbul, Turkey, May 1, 2015. (Photo by Kemal Aslan/Reuters)

A protester throws a Molotov cocktail during clashes with police in Okmeydani neighborhood in Istanbul, Turkey, May 1, 2015. (Photo by Kemal Aslan/Reuters)

Two protesters prepare Molotov cocktails during clashes with police in Okmeydani neighborhood in Istanbul, Turkey, May 1, 2015. Turkish police fired tear gas and water cannon at hundreds of stone-throwing May Day protesters on Friday, after they defied a ban and tried to march on Istanbul's Taksim Square. (Photo by Huseyin Aldemir/Reuters)

Two protesters play with Molotov cocktails during clashes with police in Okmeydani neighborhood in Istanbul, Turkey, May 1, 2015. (Photo by Huseyin Aldemir/Reuters)

A protester uses a catapult during clashes with police in Okmeydani neighborhood in Istanbul, Turkey, May 1, 2015. (Photo by Huseyin Aldemir/Reuters)

A protester plays with a ball during clashes with police in Okmeydani neighborhood in Istanbul, Turkey, May 1, 2015. (Photo by Huseyin Aldemir/Reuters)

A masked protester walks during clashes with police in Okmeydani neighbourhood in Istanbul, Turkey, May 1, 2015. (Photo by Kemal Aslan/Reuters)

A masked protester prepares to throw a Molotov cocktail during clashes with police in Okmeydani neighbourhood in Istanbul, Turkey, May 1, 2015. (Photo by Kemal Aslan/Reuters)

A masked protester holds a Molotov cocktail as he sits during clashes with police in Okmeydani neighbourhood in Istanbul, Turkey, May 1, 2015. (Photo by Kemal Aslan/Reuters)

A police officer in a gas mask looks at people watching from inside a street shop during clashes in Okmeydani neighbourhood in Istanbul, Turkey, May 1, 2015. (Photo by Kemal Aslan/Reuters)

Police officers in gas masks detain a protester during clashes in Okmeydani neighbourhood in Istanbul, Turkey, May 1, 2015. (Photo by Kemal Aslan/Reuters)

Journalists run as fireworks explode in the street during clashes with police in Okmeydani neighbourhood in Istanbul, Turkey, May 1, 2015. (Photo by Kemal Aslan/Reuters)

A masked protester holds a Molotov cocktail during clashes with police in Okmeydani neighbourhood in Istanbul, Turkey, May 1, 2015. (Photo by Kemal Aslan/Reuters)

A masked protester runs away from a water cannon's jet during clashes with police in Okmeydani neighbourhood in Istanbul, Turkey, May 1, 2015. (Photo by Kemal Aslan/Reuters)

A protester lies in front of policemen during clashes with police in Besiktas neighbourhood of Istanbul, Turkey, May 1, 2015. (Photo by Murad Sezer/Reuters)

A man walks in the street of Okmeydani neighborhood of Istanbul, Turkey, May 1, 2015. Turkish police used water cannon and tear gas on hundreds of stone-throwing protesters on Friday, a Reuters reporter at the scene said, after the demonstrators attempted to defy a ban and march on Taksim Square in central Istanbul. The slogan on the wall reads: “Shoulder to shoulder against fascism. From Berlin to Istanbul”. (Photo by Umit Bektas/Reuters)

Protesters fire firecrackers as they clash with police in Okmeydani neighbourhood of Istanbul, Turkey, May 1, 2015. (Photo by Umit Bektas/Reuters)

Turkish students dance during May Day celebrations in Ankara, Turkey, Friday, May 1, 2015. Riot police and May Day demonstrators clashed in Istanbul as crowds determined to defy a government ban tried to march to the city's iconic Taksim Square. Security forces pushed back demonstrators using water cannons and tear gas. (Photo by Burhan Ozbilici/AP Photo)

A man lies on the ground as Turkish police use a water cannon to disperse protestors during a May Day rally near Taksim Square in Istanbul on May 1, 2015. Turkish police on used tear gas and water cannon to disperse protesters marking May Day in the Besiktas district of Istanbul as they tried to move towards the Taksim Square protest hub of Istanbul. (Photo by Bulent Kilic/AFP Photo)

Protestors hold molotov cocktails during a May Day rally near Taksim Square in Istanbul on May 1, 2015. Turkish police put Istanbul under a security shutdown to thwart unauthorised demonstrations on a tense May Day, as tens of thousands of labour activists turned out worldwide to defend their rights at a time of austerity. (Photo by Yasin Akgul/AFP Photo)

Participants in a May Day rally carry flags in front of the state Capitol in Denver, Friday, May 1, 2015. (Photo by Brennan Linsley/AP Photo)

Demonstrators participate in May Day protests at City Hall in San Francisco, California May 1, 2015. (Photo by Robert Galbraith/Reuters)

Demonstrators participate in May Day protests in San Francisco, California May 1, 2015. (Photo by Robert Galbraith/Reuters)

Demonstrators participate in May Day protests in Los Angeles, California May 1, 2015. (Photo by Mario Anzuoni/Reuters)

Evan Colorado, who is one-and-a-half, holds a sign during a May Day protest in Los Angeles, California May 1, 2015. (Photo by Mario Anzuoni/Reuters)

A woman holds a sign during a May Day protest in San Francisco, California May 1, 2015. (Photo by Robert Galbraith/Reuters)

A man holds up signs during a May Day protest in San Francisco, California May 1, 2015. (Photo by Robert Galbraith/Reuters)

Demonstrators participate in May Day protests in Los Angeles, California May 1, 2015. (Photo by Mario Anzuoni/Reuters)

Women cross a street as demonstrators calling for social, economic and racial justice march in New York May 1, 2015. In New York, a crowd of protesters waved banners for Freddie Gray, a black man who suffered severe spinal injuries while in police custody, as part of a larger May 1 International Labor Day demonstration touching on workers rights and wages as well. (Photo by Brendan McDermid/Reuters)

A man passes out roses to demonstrators calling for social, economic and racial justice march in New York May 1, 2015. (Photo by Brendan McDermid/Reuters)

Demonstrators participate in a May Day rally in Los Angeles, California May 1, 2015. Protesters annually assemble on May 1, marking International Labor Day, as a day to focus attention on labor and immigration issues. Demonstrators in cities across the country also used the occasion to rally against police violence. (Photo by Jonathan Alcorn/Reuters)

Demonstrators participate in a May Day rally in Los Angeles, California May 1, 2015. (Photo by Jonathan Alcorn/Reuters)

Police use pepper spray against demonstrators during an anti-capitalist protest in Seattle, Washington, May 1, 2015. The anti-capitalist May Day march in Seattle turned violent on Friday when demonstrators threw rocks and wrenches at police, who responded by lobbing “flashbangs” and shooting pepper balls, according to police and media reports. International Workers' Day, also known as Labour Day or May Day, commemorates the struggle of workers in industrialised countries in the 19th century for better working conditions. (Photo by David Ryder/Reuters)

Demonstrators argue with Shayne Butts, who was asked by many to leave because he brought a rifle, during an anti-capitalist protest in Seattle, Washington, May 1, 2015. (Photo by David Ryder/Reuters)

Police detain a demonstrator during an anti-capitalist protest in Seattle, Washington, May 1, 2015. (Photo by David Ryder/Reuters)

A police officer prepares to fire rubber bullets at demonstrators during an anti-capitalist protest in Seattle, Washington May 1, 2015. (Photo by David Ryder/Reuters)

Police detain a demonstrator during an anti-capitalist protest in Seattle, Washington May 1, 2015. (Photo by David Ryder/Reuters)

A demonstrator swears at police while holding a middle finger up during an anti-capitalist protest in Seattle, Washington May 1, 2015. (Photo by David Ryder/Reuters)

Mike Grant also known as “Philly Jesus” marches in May Day demonstration calling for a raise of the minimum wages to $15 an hour Friday, May 1, 2015, at a McDonald's restaurant in Philadelphia. Pennsylvania State Sen. Daylin Leach, D-Montgomery, is purposing legislation to increase the minimum wages to $15, index it to inflation, and eliminated the tipped minimum wage. (Photo by Matt Rourke/AP Photo)

David Pittenger, left, argues with participants in a May Day rally in front of the state Capitol in Denver, Friday, May 1, 2015. (Photo by Brennan Linsley/AP Photo)

Venezuela's first lady Cilia Flores wears a jacket made in the colors of Venezuela's flag during a May Day rally in Caracas, Venezuela, Friday, May 1, 2015. Flores' jacket reads her name, along with her official title “Primera Combatiente”. Instead of first lady, Flores' goes by the title “First Fighter”. (Photo by Fernando Llano/AP Photo)

An opposition demonstrator, her face painted with the colors of the Venezuelan national flag and the word “Freedom” on her forehead, participates in the May Day march in Caracas, Venezuela, Friday, May 1, 2015. Pro-government and opposition workers marched today in the midst of the political and economic crisis prevailing in the country, with separate marches that took place to mark International Workers Day also known as May Day. (Photo by Ariana Cubillos/AP Photo)

An opposition demonstrator with a Venezuelan national flag draped around her shoulders, holds a sigh with a message that reads in Spanish; “Son, I keep fighting for Venezuela, so that you don't leave it, or sink with it”, during a May Day march in Caracas, Venezuela, Friday, May 1, 2015. (Photo by Ariana Cubillos/AP Photo)

Venezuela's President Nicolas Maduro, right, reads a document as first lady Cilia Flores looks after they arrived for a May Day rally in Caracas, Venezuela, Friday, May 1, 2015. Maduro said at the rally he would raise the minimum wage and pensions for retirees by 30 percent, bringing the minimum wage to around 6,700 bolivars per month. That's about $1,000 at the country's official exchange rate but less than $25 at the black market rate widely used to set many prices. (Photo by Fernando Llano/AP Photo)

A supporter of Venezuela's President Nicolas Maduro attends a rally to celebrate May Day in Caracas May 1, 2015. Maduro on Friday raised the country's minimum wage by 30 percent in an effort to protect salaries as soaring prices and a shrinking economy increasingly sting his working-class support base. (Photo by Jorge Silva/Reuters)

A supporter of Venezuela's President Nicolas Maduro attends a rally from her window to celebrate May Day in Caracas May 1, 2015. (Photo by Jorge Silva/Reuters)

A supporter of Venezuela's President Nicolas Maduro cheers as another holds a picture of Venezuela's late President Hugo Chavez during a May Day rally in Caracas, Venezuela, Friday, May 1, 2015. (Photo by Fernando Llano/AP Photo)

Venezuela's President Nicolas Maduro plays the drums as he arrives for a May Day rally in Caracas, Venezuela, Friday, May 1, 2015. (Photo by Fernando Llano/AP Photo)

An opposition demonstrator dressed in a skeleton costume with a Venezuelan national flag draped over his body, lies on the pavement, during a May Day march in Caracas, Venezuela, Friday, May 1, 2015. (Photo by Ariana Cubillos/AP Photo)

A child plays with a colored ribbon during a visit to Tiananmen Square in Beijing, Friday, May 1, 2015. (Photo by Ng Han Guan/AP Photo)

A man covered in medals leave a May Day event to celebrate China's model workers outside the Great Hall of the People in Beijing, Friday, May 1, 2015. Millions of Chinese are taking advantage of the May Day holidays to visit popular tourist sites. (Photo by Ng Han Guan/AP Photo)